The restless Earth

Question 1

Describe inner core

Answer 1

hottest part of earth
solid iron and nickel
up to 5,500 degrees c

Question 2

describe outer core

Answer 2

liquid iron and nickel

similar temperatures to inner core

Question 3

Describe mantel

Answer 3

widest section of earth
thickness= approx 2,900km
molten

Question 4

describe crust

Answer 4

thin - 0-60km

solid rock

Question 5

Compare continental crust with oceanic crust

Answer 5

C = lower density, mainly granite rock, thicker (50-60km), older (4 billion years)

O = higher density, mainly basalt rock, thinner (6-9km), younger (200 million years)

Question 6

What generates convection current?

Answer 6

radioactive decay in core

Question 7

How does convection current happen?

Answer 7

hot, less dense rises

cold, more dense falls

Question 8

What moves tectonic plates?

Answer 8

convection currents

Question 9

What is a destructive plate boundary?

Answer 9

plates move towards each other

Question 10

What do destructive plate boundaries cause?

Answer 10

violent volcanoes, earthquakes, deep-ocean trenches and fold mountains.

Question 11

Describe what happens in destructive plates

Answer 11

1. Ocean ice plate less dense so is forced under continental plate, point at which this happens is called subduction zone.
2. Oceanic plate melts due to friction and increased temp, magma forms resulting in earthquakes.
3. Magma collects to form magma chamber. Magma then rises up through cracks in continental crust. Building pressure can cause volcanic eruption.
4. Continental crust squashed and forced upwards, creating fold mountains.

Question 12

Give an example of destructive plate boundary

Answer 12

Nazca plate forced under South America plate, resulting is Andes mountain range

Question 13

What is a constructive plate boundary?

Answer 13

plates moving apart

Question 14

What do constructive plate boundaries cause?

Answer 14

less violent volcanoes and earthquakes and mid ocean ridges

Question 15

Describe what happens in constructive plate boundaries

Answer 15

1. Plates move apart so magma rises from mantel and onto surface. Earthquakes occur.
2. Magma on surface cools and solidifies, forming new crust of igneous rock. Repeats over time and eventually builds up to form shield volcano.

Question 16

Give example of constructive plate boundary

Answer 16

North American plate moving away from Eurasian plate, resulting in mid Atlantic ridge and formation of Iceland through volcanic activity

Question 17

What is a conservative plate boundary?

Answer 17

Plates slide past one another

Question 18

What do conservative plate boundaries cause?

Answer 18

frequent and violent earthquakes

Question 19

Describe what happens in conservative plate boundary

Answer 19

1. plates often become stuck due to opposing directions or different speeds.
2. Pressure builds up and causes earthquakes when released.

Question 20

example of conservative plate boundary

Answer 20

San Andreas fault - North American plate and Pacific plate moving in same direction but at different speeds

Question 21

What is a collision margin?

Answer 21

two continental crust collide and neither can sink

Question 22

What happens in collision margin?

Answer 22

1. plates push into eachother, forcing material to be folded up into huge mountain ranges. Pressure may also cause earthquakes

Question 23

example of collision margin

Answer 23

Indian plate collided with Eurasian plate to form Himalayas

Question 24

where do fold mountains form?

Answer 24

destructive and collision plate boundaries

Question 25

Describe formation of fold mountains

Answer 25

1. sediments accumulate in geosynclines 2. As plates move together, rocks start to form folds which have anticlines and synclines. These are pushed upwards to form fold mountains

Question 26

What is the case study for fold mountains?

Answer 26

the Alps

Question 27

Describe the case study for fold mountains

Answer 27

Alps. location: Central Europe Formation: African plate collided with Eurasian plate uses: farming - cattle and sheep on mountains and crops of valley floor Tourism - winter sports e.g. skiing HEP - steep terrain, high rainfall and snowmelt = lots of water to HEP plant. HEP in Alps provides 60% Switzerlands energy Mining - previously used to salt, iron ore, gold, silver and copper mining but cheaper competition and meant companies leave Alps. Adaptations: Farming - use technology to reduce transhumance. Farming space decreases and tourism increases so new methods e.g vineyards on sunny, South facing slopes tourism - stable income all year by introducing summer activities eg hiking and climbing

Question 28

Where do volcanoes form?

Answer 28

destructive and constructive plate boundaries

Question 29

describe formation of volcanoes

Answer 29

1. magma rises through cracks/weaknesses in Earths crust. 2. pressure builds up inside Earth 3. magma explodes to surface when pressure released, causing volcanic eruption 4. lava from eruption cools on surface to form new crust 5. this process repeats over time and rocks builds up to form volcano.

Question 30

Describe the inside of a volcano.

Answer 30

Magma chamber - collection of magma inside earth main vent - main outlet for magma to escape secondary vents - smaller outlets for magma to escape crater - created after eruption blows top off volcano.

Question 31

What is a active volcano

Answer 31

erupts frequently

Question 32

what is a dormant volcano

Answer 32

temporarily inactive but not fully extinct

Question 33

what is an extinct volcano

Answer 33

never likely to erupt again

Question 34

Where are shield volcanoes located?

Answer 34

constructive ate boundaries

Question 35

how are shield volcanoes formed?

Answer 35

eruptions of thin, runny lava

Question 36

Characteristics of shield volcanoes

Answer 36

low gentle sloping sides frequent but gentle eruptions

Question 37

location of composite volcanoes

Answer 37

destructive plate boundaries

Question 38

characteristics of composite volcanoes

Answer 38

made up of alternating layers of lava and ash eruptions may be a pyroclastic flow

Question 39

what is a pyroclastic flow?

Answer 39

mixture of hot steam, ash, rock and dust. high speed and temperatures of 400+ degrees

Question 40

give positive effects or eruptions

Answer 40

dramatic scenery created which attracts tourists lava and ash deposited breaks down to provide nutrients for soil geothermal energy

Question 41

give negative effects of eruptions

Answer 41

loss of lives landscape can be destroyed forever Lahars can be created if ash and mud mix with water

Question 42

what is a lahar

Answer 42

fast moving mudflow

Question 43

What is the case study of volcanic eruption

Answer 43

Chances Peak, Monserrat (1995-97)

Question 44

Name the layers of the earth in order

Answer 44

Inner core Outer core mantel crust

Question 45

Describe case study of volcanic eruption

Answer 45

Location: small island in Caribbean Before 1995 it had been dormant for over 300 years warning signs of eruption in 1995 effects: 19 people killed Homes and buildings destroyed including hospital and transport links Plymouth (Capitol City) covered in mud and ash Short-term responses: